How to Rid Your Garden of Cucumber Beetles

Updated on January 18, 2015

Striped Cucumber Beetle | Source

Contrary to their name, cucumber beetles prey on more than cucumbers. Their preferred menu includes any plant in the cucurbit family: cucumbers, melons, squash and pumpkins. They not only destroy plants by eating them but they are also a vector for disease spreading bacterial wilt and mosaic virus for which there are no remedies other than to remove the diseased plants from your garden and compost them.

Cucumber beetles come in four varieties: Eastern and Western Striped Cucumber Beetles and Eastern and Western Spotted Cucumber Beetles. To rid your garden of them, it is important to understand their lifecycle.

Spotted Cucumber Beetle | Source

Know your enemy!

Adults overwinter in your garden amongst woody areas and the weeds and garden debris that are leftover from the growing season. When spring arrives and the temperature reached the mid-50’s, they emerge and start eating the leaves and petals of the available flowering plants. As the season progresses and temperatures continue to rise, they switch to their favorite cucurbits as they germinate. They favor the stems and leaves.

They also begin mating. The female striped cucumber beetle can lay up to 1500 eggs in her short two month lifetime. The female spotted cucumber beetle “only” lays 200 to 300 eggs. The eggs are laid in the soil close to your cucurbits. When they hatch, the larvae eat the roots of your plants.

The southern US with its warmer temperatures and longer growing season supports up to three generations of cucumber beetles each year. The colder northern US usually sees only two generations.

Now that you know a little bit about their lifecycle, here are some suggestions for ridding your garden of these pests.

Make them think there is nothing to eat

Try planting your cucurbits two weeks later than you normally would. Cucumber beetles are not the smartest creatures and will think that no cucurbits will be grown in your garden so they will move on in search of their favorite food.

You can also try planting a “trap crop”. If you are trying to grow cucumbers, plant another cucurbit around the perimeter of your cucumber patch. Blue Hubbard squash is usually recommended because it can withstand being eaten by cucumber beetles and is resistant to bacterial wilt which is carried by them.

Use barriers

Barriers are also effective. Plant your cucurbits under floating row covers. Just remember to remove them for a few hours a day while your plants are flowering to ensure pollination. If the cucumber beetles can’t reach them, neither can the pollinators.

Place foil around your plants. Cucumber beetles don’t like the reflectiveness. Use mulch around your plants to deter cucumber beetles from laying their eggs near your plants. You can use your normal straw or hay mulch or use the foliage from plants that repel cucumber beetles like radishes, tansy and nasturtium.

Speaking of which, plant radishes, tansy and nasturtium amongst your cucurbits to make them less inviting to cucumber beetles.

The enemy of my enemy is my friend

Plant flowers like marigolds, sunflowers, daisies and alyssum, or herbs such as borage, catnip, calendula and dill to attract beneficial insects which view cucumber beetles as lunch. You want to attract predators such as soldier beetles, braconid wasps and tachnid flies. Nematodes which live in the soil will eat cucumber beetle larvae after they hatch but before they can damage the roots of your cucurbits.

Use your fingers

If you choose to handpick cucumber beetles off of your plants, do so in the mornings and evenings when they are less active. During the day, they will fly away faster than you can grab them. Wear yellow, which they find attractive, so that when they do fly away, it will be only as far as your shirt.

Use your chickens

Chickens love insects and grubs! If you raise chickens, or have a neighbor who is willing to lend you their chickens for a few hours in the evening, you can set up a temporary pen around your cucurbits and allow the hens to help themselves to an evening snack of cucumber beetles on your plants and their larvae in the soil.

Fall cleanup is imperative

The most important step you can take to prevent cucumber beetles from destroying your cucurbits is to prevent them from overwintering in your garden. Remove all debris, dead plants and weeds from your garden in the fall and do a deep tilling. The cleanup deprives them of hiding places for the winter and the deep tilling exposes any hidden beetles to the harsh winter weather which will kill them.

A severe infestation of cucumber beetles can destroy your cucurbits within weeks. There are simple, organic steps that you can take to reduce the number of cucumber beetles and minimize the damage they inflict and diseases which they carry.